Atomic Theorists

How we got to where we are now

Law of Conservation of Mass

• Matter can’t be created or destroyed

• Who: Antoine Lavoisier

• When: 1785

• Where: France

Law of Definite Proportions

• Compounds = Elements put together in

fixed whole number ratios

C + O2 CO2

• Who: Joseph Proust

• When: 1797

• Where: France

Law of Multiple Proportions• Two elements can form more than one

compound

• The ratios of elements will be small whole numbers.

• Who: John Dalton

• Where: England When: 1803

What: All matter is a combo of fire, air, earth or water

When: 350 B.C.

Where: Greece

Who: Aristotle

Who: Democritus •When: 400 B.C.•Where: Greece•What: Matter was made of indivisible substances he

called atomos (1st talk of the atom)

What: Solid Sphere Model (1st atomic theory)

•Matter is made up of indivisible particles •All atoms of a particular element are identical •Different elements are composed of different kinds of atoms. •Compounds are composed of atoms in specific ratios. •Atoms are not created or destroyed in a reaction.

When: 1805 Where: England

Who: John Dalton

How did Dalton do ?• Matter is made up of indivisible particles

No. Atoms can be divided

• All atoms of a particular element are identical

No. Doesn’t account for isotopes

• Different elements are composed of different kinds of atoms.

Yes!

• Compounds are composed of atoms in specific ratios.

Yes!

• Atoms are not created or destroyed in a reaction.

Yes!

What: Atoms aren't smallest particle

•Conducted experiment with a Cathode Ray Tube

•Particles had a negative charge(discovered electrons)

•Model = plum pudding

When: 1897 Where: England

Who: J.J. Thomson

Cathode Ray Tube

What: •Experiments to determine mass of electron

•Conducted the oil drop experiment

•Verified that electron is negatively charged

•No new model

Where: America When: 1910

Who: Robert Millikan

MillikanOil Drop Experiment

Who: Ernest Rutherford

What:

• Conducted Gold Foil experiment

• Proved nucleus is dense, positively charged core of atom

• When: 1911

• Where: America

Model = Planetary Model

Rutherford’s Experiment

Gold Foil Experiment

Who: Niels Bohr

• What: Pulsating Planetary Model

• Electrons can move between energy levels

• When: 1913

• Where: Denmark

Who: James Chadwick

What:

• Confirmed existence of neutron

• No new atomic model

• When: 1932

• Where: England

Whose model of the atom is represented by this diagram?

Aristotle

Democritus

Dalton

Thomso

n

Milli

kan

Rutherf

ord Bohr

Chadwick

0% 0% 0% 0%0%0%0%0%

1. Aristotle

2. Democritus

3. Dalton

4. Thomson

5. Millikan

6. Rutherford

7. Bohr

8. Chadwick

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

21 22 23

Whose model of the atom is represented by this diagram?

Aristotle

Democritus

Dalton

Thomso

n

Milli

kan

Rutherf

ord Bohr

Chadwick

0% 0% 0% 0%0%0%0%0%

1. Aristotle

2. Democritus

3. Dalton

4. Thomson

5. Millikan

6. Rutherford

7. Bohr

8. Chadwick

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

21 22 23

Whose model of the atom is represented by this diagram?

Aristotle

Democritus

Dalton

Thomso

n

Milli

kan

Rutherf

ord Bohr

Chadwick

0% 0% 0% 0%0%0%0%0%

1. Aristotle

2. Democritus

3. Dalton

4. Thomson

5. Millikan

6. Rutherford

7. Bohr

8. Chadwick

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

21 22 23

Whose model of the atom is represented by this diagram?

Aristotle

Democritus

Dalton

Thomso

n

Milli

kan

Rutherf

ord Bohr

Chadwick

0% 0% 0% 0%0%0%0%0%

1. Aristotle

2. Democritus

3. Dalton

4. Thomson

5. Millikan

6. Rutherford

7. Bohr

8. Chadwick

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

21 22 23

Whose model of the atom is represented by this diagram?

Aristotle

Democritus

Dalton

Thomso

n

Milli

kan

Rutherf

ord Bohr

Chadwick

0% 0% 0% 0%0%0%0%0%

1. Aristotle

2. Democritus

3. Dalton

4. Thomson

5. Millikan

6. Rutherford

7. Bohr

8. Chadwick

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

21 22 23

Whose model of the atom is represented by this diagram?

Aristotle

Democritus

Dalton

Thomso

n

Milli

kan

Rutherf

ord Bohr

Chadwick

0% 0% 0% 0%0%0%0%0%

1. Aristotle

2. Democritus

3. Dalton

4. Thomson

5. Millikan

6. Rutherford

7. Bohr

8. Chadwick

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

21 22 23

Whose model of the atom has the name “Planetary Model”?

Aristotle

Democritus

Dalton

Thomso

n

Milli

kan

Rutherf

ord Bohr

Chadwick

0% 0% 0% 0%0%0%0%0%

1. Aristotle

2. Democritus

3. Dalton

4. Thomson

5. Millikan

6. Rutherford

7. Bohr

8. Chadwick

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

21 22 23

Whose model of the atom has the name “Solid Sphere”?

Aristotle

Democritus

Dalton

Thomso

n

Milli

kan

Rutherf

ord Bohr

Chadwick

0% 0% 0% 0%0%0%0%0%

1. Aristotle

2. Democritus

3. Dalton

4. Thomson

5. Millikan

6. Rutherford

7. Bohr

8. Chadwick

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

21 22 23

Whose model of the atom has the name “Pulsating Planetary Model”?

Aristotle

Democritus

Dalton

Thomso

n

Milli

kan

Rutherf

ord Bohr

Chadwick

0% 0% 0% 0%0%0%0%0%

1. Aristotle

2. Democritus

3. Dalton

4. Thomson

5. Millikan

6. Rutherford

7. Bohr

8. Chadwick

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

21 22 23

Whose model of the atom has the name “Plum Pudding”?

Aristotle

Democritus

Dalton

Thomso

n

Milli

kan

Rutherf

ord Bohr

Chadwick

0% 0% 0% 0%0%0%0%0%

1. Aristotle

2. Democritus

3. Dalton

4. Thomson

5. Millikan

6. Rutherford

7. Bohr

8. Chadwick

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

21 22 23